GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Defogger Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Start the engine.
  2. Command the rear window defogger indicator ON and OFF, by depressing the rear window defogger switch.
  3. Observe the rear window defogger indicator.

Does the rear window defogger indicator turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Test the defogger ON signal circuit of the rear window defogger switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 5

Go to Step 4

4

Replace the defogger switch.

Did you complete the replacement?

Go to Step 5

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5

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2